Automatic means for caging gyroscopes



'APA-21,1942. 3. .\ARL1ON 280,116

- AUTOMATIC MEANS FOR GAGING cyYRoscoPEs Filed arch :5, 1939 sshuts-sheet 2 April 21, 19424 i a. j, V' :Al=u.sc '|-1 -1 2.280.116 lAUTOMATIC MEAris-on CAG-ING GYRoscoPEs I l Filed March s, 193,9V l s'sheetsA-sheet s 'Hhs TTORNEY ,ally perpendicular axes of 4support andtions.

'a llxed matic pilot butunder v.action of the gyroscopic controls andVan angle of attack,

' mano puoi of the Patent No. 1,992,970, dated Maron 5, 1935, n. A.`Sperry, Jr., M. F.

Patented Apr. 21, 1.942

AUTOMATIC MEANS FOB. CAGING l GYROSCOPES am G. Carlson,

Freeport, N.` Y., assigner to Sperry Gyroscope Company, Inc.,

incorporation of New York Brooklyn,

Application March s, 1939, serial No. 259,590

This invention relates to gyroscopes mounted infgimbal bearings forfreedom about two mutumore specifically `to automatic means for cag-.ing such gyroscopes or preventing rotation about their support axesunder predeterminedv cindition is aircraft to maintain an airplane inlevel flight andon course in azimuth or to cause it to'climb and/or`bank at predetermined angles. Under in connection with. automaticpilots for o ordinary `flight conditions the operation of the entrustedto vthe autoairplane4 may be safely l certain' abnormal conditions itmaybeeomenecessary to suspend the effect a quick change in operatingprocedure. It is a well known fact that when an airplane ls operated attoo slow a speed or at too great there is the possibility that a suddenchange of attitude due to a gust of air may cause it to stall and gointo a spin. lThis element of danger is especially pronounced in theoperation of fast military pursuit ships having an airplane no longerment of its control surfaces in the normal inanner and it'has been foundthat the proper procedure under these circumstances is immediately tobring the ailerons and elevator to their cenit refers relatively highstalling speeds. When stalled, y responds to the move- -(me importantapplication of my inven- 5 claim. (c1. 244-79) artificial horizont, has`two air pick-oils acting through suitable servo systems to move thecontrol surfaces in a manner which, under normal flight conditions,`returns the ship to the attitude for which the automatic pilot is setwhen it departs from that attitude. Since th bank and climb gyro doesnot distinguish between normal and abnormal flight conditions, when inwhich gyroscopic controls are used a change of attitude occurs which issuflicient to stall the ship and thereby make necessary a changed method'of lcontrol, the gyroscope, by moving the control surfaces in the usualmanner, not only aggravates the condition, but makes 'to the verticaLltwill it impossible to bring the ship out of the resulting spin. o

Qne object of my invention is to provide quickacting automaticV meansfor'cagin'g the bank and climb gyrQ" thereby centralizing the controlsurfaces when for any yreason the plane departs from the attitude atthan an adjustable, predetermined angle. When vHaring speed has beenrecovered after a stall, and asit preeesses back the gyro may be uncaglevel out the airplane. This of course. may be speeded up by operatingthe bank and/or climb knobs of the automatic pilot, as nis done withoutautomatic caging.- In addition to the function above described myinvention also ,provides a safety feature to tral positions and holdthem there until sufo cient air speed has been attained to insurecontrol by theusual method. As at present de v signed. no .automaticpilot will achieve this re the pilot will place the manual caging of thesuit, but on the contrary control surfaces in` an extreme pomtion.

My invention is shown as applied to an autogeneral type shown' in priorBates, and applicant, inventors. The function of maintaining theairplane in level flight or at a predetermined rate of climb and/orangle of bankl is governed bya gyroscope rotating about a vertical axisand mounted for freedom about two horizontalaxes of support; Thespinning axis is maintained vertical by any of well known erectionmeans, such as shown prevent upsetting the ceases hard over flmction. Y

The automatic cagingmeans provided by my airplane if the gyro prethroughfailure of some part to linvcr'ition may' be engaged or disengaged atwill and does not. interfere with the conventional gyroseope.

Other objects and advantages of ,this inventionwill become apparentasthe description pro- Although my invention has been described in itsapplication to automatic pilots for airplanes, f

it will be obvious that it is not restricted to such application" butmaybe used for the automatic l caging of any airplane gyroscope havingnormal freedom about a pluralityof axes.

Referring to the drawings showing oneform t of my invention:

in the' aforesaid patent and in my prior Patent t 1,982,636, datedDecember 4, 1934, vfor Air driven gyro verticals. Such a gyroscopeconstitutes an artificial horizon and provides a stabilized referenceplane from which angles `^oi' bank and climb are measured. Thisinstrument, known- A ing solenoid andlmeans forv mati'cto manuarcaging'o ,o

Fig. 3 is an elevation showing the gyrosc'ope Fig. 1 is a plan view,partly in section, showing my invention mounted on a housing forfagyroscope-l F'ig.v` 2 is a partial` elevation showing the cagwhich itisflying by more changing from autcschematic diagram showing my Fig. 8 isa'detail of one of the air pick-offs from a control gyroscope of anautomatic pilot. My invention is shown in connection with a gyroscopespinning about a vertical axis and mounted in a support allowingrotational freedom about two horizontal axes. Ais the rotor of thegyroscope which is preferably airspun although obviously other means forspinning the rotor may be adopted, and 2 is the casing or rotor bearingframe in which the rotor bearings are mounted. Said casing is shown aspivoted on a Aminor axis 40-40 'within gimbal ring 3, which in turn ispivoted on major axis 42-42' in fixed brackets 4|. The gyroscope isnormally maintain vertical by gravitationally responsive means shown asa plurality of small pendulums 50 pivoted on a downward extension of thegyro case and cooperating with air ports 5| therein, as shown more indetail in the aforesaid patents. For picking off the relative motion ofthe gyroscope about its minor axis, I have shown a bail 4 pivoted onaxis 43--43' normally in line with axis 40-40, a sliding connectionbeing provided between thebail and the gyroscope by means ofthe usualchannel 44 in the bail and a roller 45 on a pin 45 projecting from thecasing 21 A portion of the housing for theinstrument is shown at 5,which supports the brackets for the gimbal ring and 46 for the bail. Forcentralizing the gyroscope, I have shown projecting from' the lower partof the gyro case a pin 6. The caging mechanism proper is automaticallycontrolled by a solenoid 1 having a plunger 8 and'a thrust rod 9 guidedin suitable bearings with a collar Ill of lnsul-ating material mountedthereon. Collar Il) is pivotally connected to one of a plurality offingers pivotally connected by a 'plurality of links I3 and pivotallymounted on a ring material in such a manner` that the movement ofsolenoid plunger 8 from its non-operated to its operated position withinthe winding simultaneously rotates all of fingers about their pivots,causing the severaltlngers to close inwardly engagingpin 6 at anyposition itmay occupy and move said pin to a central position withrespect to the housing. The rotor is thuscaged and secured againstrotation about the gimbal axes. Since ring I4 on which caging fingers `Hare pivoted and collar Il on the solenoid thrust rod are both made ofinsulating material, theV caging fingers have no electrical 'connection4to the housing in their normal non.-

operated condition.

Means for caging the gyroscope manually and for disconnecting theautomatic caging circuit is provided by caging knob I6 bearing andndexI1 readable upon markings on escutcheon ,plate I8 and attached to cagingknob shaft I9 at one extremity. A sector 28 mounted on shaft |-9 havingan arcuate slot through which shaft 9 passes, permits translationalmotion to .be transmitted from shaft,l I9 to rod 8 by.engagf |4 ofinsulating f ailerons 38 and elevator 39 respectively. caging of thebank and climb gyro by the mounted in awell known type of gimbal supporting collars I0 and 2| while allowing independent rotation of shafty I9limited by said slot. Thus, by pulling knob I6 outwardly away from thehousing, caging fingers Il are operated in the same manner as when thesolenoid is energiZed.

A cam 22 of insulating material carried by shaft I9 engages a leafspring 23 insulated from the housing, having a contact 24 cooperatingWith contact 25 on a second spring 26, said second spring being groundedor electrically connected to the housing. Connecting lugs 21 and 28provide means for making an electrical connection to switch springs 23and 26 respectively. In the position shown with knob I6 turned to theright, contacts 24 and 25 form an electrical connection. When, however,knob I6 is rotated to the left, cam 22 raises spring 23 and breaks thisconnection. There are four possible positions which knob |6 may occupy:(a) in and rotated to the right (b) in and rotated to the left (c) outand rotated to the right (d) out and rotated to the left. ing a springloaded ball 29 and four suitably located depressions on the periphery ofsector 20 holds the caging mechanism in any of the four positions towhich it is operated.

Referring to Fig. 6 and assuming caging knob 'ls to be in and rotated tothe right, the cir-y cuit in which the winding of solenoid 'I isserially connected may be traced as follows: starting at the housing, tolug 28, spring 23, contact 24,contact 25, spring 26, lug 21' to one poleof a battery of suitable voltage or other source of E. M. F.; throughthe battery to the opposite pole, through the' winding of solenoid 1 tocaging fingers This circuit is completed when any of caging fingersengages pin 6, said pin being electrically connected to the housingthrough the gimbal bearings. The arc through which the housing 5 mustswing from its normal position to bring any of caging fingers in contactwith pin 6 is adjusted by positioning collars 2| and |0 on shaft 9.

The association of my invention with the bank Sperry, Jr., M. F. Batesand applicant and willl not be discussed in detail here. The type ofpick-ofi' referred to is` illustrated in Fig. 8 which shows two airports 3|)V through.y which air is continuously drawn and whose openingand closing is differentially controlled by shutter 3|. The pick-offsthrough air relays 32 and 33 and balanced oil valves 34 and 35 controlthe operation of servo motors 36 and 31 which position The operation ofsolenoid 1 centralizes the `two shut- .ters 3| and equalizes theopenings of their associated air ports, thereby causing servo motor 36and 31 through the means described to bring ailerons 38 and elevator 39to a central position and hold them, in such position.

` Thel operation of my invention in its application to automatic pilotsis briefly as follows: When flying at speeds at which there is littlepossibility of stalling even if a relatively large change of attitude ofthe ship occurs, caging A detent includ-l knob is wm be 1nthe positionif the ship no w, changes attitude to the SupPOl't, 4and a.

and rotated to the left with index I1 at the position Auto cage oif."This breaks the connection between contacts-2l and 25 and preventssolenoid I from becoming energized. At slower speeds when a suddenchange of attitude might stall the ship and throw it into a spin, knobI6 is rotated to the right to Auto cage on. 'I'his establishes laconnection between contacts 24 and 25 so that by more than apredetermined angle which'may be, for ex/ample, of theorder of l to 40degrees longitudione of caging fingers `collar I0 causes caging fingersIl to move in.

Wardly and bring pin 6 toa central position and holdit there. Thiscentralizing of `the spinning axis of the spect to the housing of the"instrument causes ated controls to central positions ment oflongitudinal and lateral control of the airplane. At any time thereafterat the discretion of the human pilot.' the bank and climb gyro" may beuncaged by turning knob IB to the left to the position Auto cage off.'This breaks the solenoid bring these surfaces to their The gyro may becaged manually at any timeV by pulling out knob I6 regardless of theposition to which this knob is rotated. Preferably, however, the knobwill be rotated to theleft so that solenoid 1 will not be energizedlwhencaging ngers l I engage pin 6.

As many changes could be made in the above construction and manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof,

This movement of the plunger,

bank and climb gyro with re' of electromagnetically operated means,means scope of an automaticpilot `rotor bearing frame mounted for normalfree- 2. The `combination with having a rotorand dom about two mutuallyperpendicular gimbal axes and gravity controlled erection means formaintaining the spin axis of said rotor vertical,

attached to said rotor bearing frame and cooperative stationary meansfor controlling said electromagnetic means and a cage operatedby saidelectromagnetic means for positioning said nally, laterally, or in anintermediate direction,

` II will be brought in con-'f tact with pin '6, thereby completing thecircuit i tical, means including movable control surfaces v saidgyroscope .and housing for maintaining the 4 the associated elevator andaileron servo-oper? and permits the reestablish-V circuit at contactsv24 and l Y 25 and deenergizes the rotor bearingv frame and securing itagainst rotation about said gimballaxes, thereby rendering the bank andclimb control of the. automatic pilot inoperative. -f

3. Gyro-vertical apparatus for automatic control of the flight of anaircraft, comprising a .housingxed relative to the craft, a gyroscopemounted on said housing for three degrees of freedom, maintainingthespin axis of said gyroscope verof the craft actuated by relativemotion between craft in a desired attitude relative to the horizontal,and caging means to immobilize said gyroscope relative to said housingupon predetermined departure of the craft from said attitude,

said control surfaces being thereby moved to andheld in a preferredposition.

4. -Means forautomatically rendering the bank and climb controll of anautomatic pilot inoperative under abnormal flight conditions, comprisingcooperative contact means' mounted respectively on the rotor bearingframe of the vertical gyroscope lof said control and on the craft forengagement upony predetermined departure of the craft from a'setattitude relative to the horizontal in any direction, and means actuatedi upon engagement of said two contacts to cage said gyroscope in fixedrelationship to the axes of said craft, thereby causing said pilot tomove 4,a control surface or surfaces determining the atit is'intendedthat all matter 'contained in the" above description` or shownin the accompanying drawings'shall'be interpreted as illustrative andnotin a limiting sense.

Having described my invention, whatv I claim 4 and desire to secure byLetters Patent is:

1. The combinationwith a gym-verticaifhaving a rotor and-rotor bearingframe and an outer supportinounting said framefor freedom about twomutually perpendicular axes, of a gravitationally responsive means fornormally maintaining sition, the gyroscope vertical, an automaticallyopered on said housing vtitude of said craft to a preferred position andthere hold said surface or surfaces immobilized. 5. Automatic cagingmeans for a gyroscope having a housing, a rotor and a rotor bearingframe mounted on said housing. for freedom about two perpendicularsupport axes, comprising a contact member mounted on and extending fromsaid frame along the spin axis of said rotor. a plurality of cagingmembers movably supportand normally spaced .from said contact member,said caging members each having an electrically conducting portion,means for simultaneously operating said caging members to causeengagement with said contact member and thereby'cause positioning ofsaid frame in a preferred position, said frame being immobilized by saidcaging members in said poment oi said contact -member and the conductingportion of any of said caging memberslfor actu ating said last namedmeans. l

:BERTQ CARLSON.

the vertical lgyra' gravity 4controlled means for normally l and circuitmeans controlled by engage-

